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The Most Sacred and Most Unofficial Quake Technical Specification.
As derived by Nezu the Unworthy
(montanuy@dmi.ens.fr)
From the holy Long Words of the id Gods
found in an Ancient Scroll retrieved by the Vandals
and read according to the Lores of the Cavemens.

Sure, go ahead. But all that info is way outdated. Everything has changed.
-- John Romero

List of Contents

0 Introduction
1. New WAD file
1.1 Directory
1.2 Pictures Format
1.3 Wall Textures Format

2. Level Maps
2.1 Organisation
2.2 Level
2.3 Sectors
2.4 Walls and Skies
2.5 Texture references
2.6 Planes
2.7 Vertex
2.8 Nodes
2.9 Visibility lists
2.10 Light maps and lighting
3. Entity Models
3.1 Organisation
3.2 Animation

4. Sound Capabilities
4.1 Sound format
4.2 Sound spatialisation

5. Network Capabilities

6. Miscellaneous Information
6.1 The Quake programming language
6.2 Definition of entities
6.3 Definition of light maps

7. Final word

0. Introduction

I know that it's completely ridiculous to publish specification of a game that is not finished, and that is not even supposed to be available to anyone.
So this document is in no way a definite specification of Quake, and all that is described here will be totally obsolete by the time Quake is released. In fact, it should become obsolete as soon as id software releases official specification, if they bother to.

The only purpose of this document is to make you familiar with the general structures and concepts of Quake editing.
There is not enough information here for you to start writing an editor for Quake, not even enough to start making an actual Quake level. But there are enough hints to enable you to prepare the materials, and start planning things.
There is also more than enough for you to start dreaming a bit, while the id guys are still busy on the code.


Legal Warning

Quake and DOOM are Trademarks of id Software, inc, hereby acknowledged. The technical details presented here are all Copyright id Software. This document is not an official id Software publication.
Do not bother id Software concerning the contents of this file.
Descent is a trademark of Interplay. Dark Forces is a trademark of Lucas Art.

This document is copyrighted. You are not allowed to publish it via any electronic or non-electronic means without the explicit consent of id software. You are not allowed to put any part of this document on non-free support (like magasines, newsletter or CD-Rom) without my prior consent.
In no event shall I be held responsible for any degradation of your health, wealth, mental sanity or social relations.
All rights reserved. No guaranty. That's life!


Thanks
This document would not have been possible without the hard work of id software and some hackers whose name is not public. I think I did my share of hard work, but it was considerably easier than what any of them did. So mainly thank them, not me!

Special Thanks to Jens Hykkelbjerg for the first HTML version.


1. The new WAD2 format

It is expected that the WAD2 format is only temporary. Quake will probably directly read common picture and sound formats. However, stuff like MIP textures and Alias models might not be very easy to store in a traditional file format, so it is still possible that WAD remain in use.

1.1 Wad Directory

// WAD Header
struct QKHEADER
{ char Magic[4]= "WAD2";  // Name of the new WAD format
  long NbOfDirEntries;    // Number of entries
  long DirPosition;       // Position of WAD directory
};

// Directory
struct QKENTRY
{ long Start;             // Position of the entry in WAD
  long Wsize;             // Size of the entry in WAD file
  long Size;              // Size of the entry in memory
  char Ident;             // Entry identification
  char Cmprs;             // Compression
  short Dummy;            // Not used
  char Name[16];          // 1 to 16 characters, '\0'-padded
} Dir[NbOfDirEntries];    // like in DOOM

1.1.1 Entry identification

The field Ident in the directory identifies the entry. It's a single byte, which give 256 possibilities. Only 3 are actually used for the moment.
0x40= '@'= Raw bytes (Console, Color Palette)
0x42= 'B'= Pictures (for status bar)
0x44= 'D'= MIP Textures (for 3D brush models)

1.1.2 Color palette Format

All the pictures, textures, sprites and alias model skins use color indexes in a 256-color table, and it can be expected that only a limited set of color palettes will be used. Maybe just one. At least, it's pretty sure that there is only one color palette for all the textures.

This format is Exactly the same as in DOOM:

struct RGB {char R; char G; char B;} Palette[256];
Internally, the color palette is translated into a much bigger structure, that takes into account the light level, just like in DOOM. This structure depends on the number of colors available on the display, so it might be calculated by the engine at startup.

1.1.3:Console lump format

The exact usage of the console is not known. Chances are that it's some kind of text mode that is used when starting the game, or when connecting to a server, in the great id software tradition of not wasting any time on useless animation sequences.

Modifying the console lump is of very limited interest. Here is roughly the format:
The console lump is a similar in structure to the flat pictures of DOOM. It's a simple lump of color indexes:

char  Console [192][128];  //This means it's a 128x192 array
The first 64 rows are devoted to the decription of the character font (each ASCII character below 0x80 has a 8x8 cell attached to it. The characters below 0x20 are special).

The rest of the picture is made of four 64x64 quadrant: one grid, and threes other with somewhar random texture. These might be some background for the level maps. Who cares actually?

1.2 Picture Format

The pictures will probably used for everything concerning the status bar (animations, numbers, ...). They are not used for sprites, countrary to DOOM.

This is essentially the same format as in DOOM, except that the picture is drawn by row, not by columns, and that 16-bit numbers are used, because a screen is 320 or 640 wide.

// Picture header
struct QKPIC
{ long Width;           // Picture width
   long Height;          // Picture height
  long Row[Height];     // Offset to the rows, from start of picture
}

// Each column is a set of lumps, placed one after the other.
// if for a lump Hpos=0xFFFF, then it's the end of the set.
struct PICLUMP
{ short Hpos;           // Horizontal offset
  short Count;          // number of pixel
  char Pixel[Count];    // pixels color index (in current palette)
  char Dummy[Count&1];  // to align the structure PICLUMP on 16-bit boundary
}

1.3 Level Wall Textures

The MIP Textures are very special pictures, made of a set of 4 pictures, scaled by 1, 1/2, 1/4 and 1/8, in order to avoid the Aliasing effect that made DOOM walls and floors look so jerky in the distance.

Those textures are used to cover the walls, the floors, the ceilings and the skies surfaces. Actually, they just cover any surface. Those textures are NOT used for sprites or Entity models, so those models are not (yet?) protected from ugly aliasing effects.

1.3.1 Texture names

The names of textures can contain up to 16 characters.

If the texture is not animated, the name can be anything, provided the first character is not '*', the asterisk.

1.3.2 Animated Texture names

If the texture is animated: So for instance an animated sky will be composed of 3 textures:
  1. *02cloudsky
  2. *12cloudsky
  3. *22cloudsky

1.3.3 Texture Lump format

When stored in a WAD, the MIP textures are made of just one lump, containing a header, then the texture scaled by 1, then by 1/2, then by 1/4, then by 1/8.

//Texture header
struct TEXHEAD
{ char Name[16]         // Texture name, useless. To be removed?
  long W;               // Width
  long H;               // Heigth
  long Scale1Pos;       // pointer to Tex, scaled 1
  long Scale2Pos;       // pointer to Tex, scaled 1/2
  long Scale4Pos;       // pointer to Tex, scaled 1/4
  long Scale8Pos;       // pointer to Tex, scaled 1/8
}
// At offset Scale1Pos, from start of file
// Picture, scale 1
char Tex1[ W*H];
// At offset Scale2Pos, from start of file
// Picture scaled by 1/2
char Tex2[ (W/2)*(H/2)];
// At offset Scale4Pos, from start of file
// Picture scaled by 1/4
char Tex3[ (W/4)*(H/4)];
// At offset Scale8Pos, from start of file
// Picture scaled by 1/8
char Tex4[ (W/8)*(H/8)];
All those Tex1, Tex2, Tex3, Tex4 represent color indexes, And the picture is 256 colors. The picture palette is usually indicated in the begining of the WAD that contain a set of textures.

The color palette index zero is used to represent transparency.

1.3.4 Texture Anti-aliasings

(Nonsense ahead. Go get some Aspirin)

The sampling theorem states that when you sample any signal (sound, picture, anything) the highest frequency contained in this signal must be at most one half of the sampling frequency. If there is any frequency above that, the sampling process will map it into a lower frequency, thus creating a terrible mess into the sampled signal. This mess is called Aliasing.

When you try to display a picture on a smaller space, you increase all the frequencies contained in that picture, and thus risk Aliasing. That's basically what happend in DOOM at long distance.

Now, all you need is only to low-pass filter the picture, with a cut frequency equal to half the sampling frequency. Easy! But... There is no DSP on the video memory, so those calculations would take too much time.
It's much easier to pre-calculate 4 scaled down pictures, that can be used across the most common range of scales:
infinity-1, 1-1/2, 1/2-1/4, 1/4-1/8.
Below 1/8, there will be some aliasing...

Here is how the right texture is selected in Quake:

int R_MipLevelforScale(float scale)
{
  if(scale>= 1) return 0;       // 1 and above. no aliasing.
  if(scale>= 0.4) return 1;     // shouldn't it be 1/2 ?
  if(scale>= 0.2) return 2;     // shouldn't it be 1/4 ?
  return 3;                     // down to 1/8 (below, aliasing!)
}

2. Level Map structures

The level structure looks fairly complex, but it contains only the minimal amount of information. In that respect, it is much cleaner than the level structure of DOOM. It seems clear that with Quake, id has learnt how to make almost optimal use of 3D BSP tree.

This 3D structure is real simple compared to the formats used by 3D Studio or even POV, so conversion should be possible.

However, Quake will also necessitate 3 special structures which are not common to 3D graphic packages:

  1. A 3D BSP tree, optimised for speed (minimum number of face splits, and minimum number of nodes and leaves). It's not that hard to calculate, but it's hard to optimise correctly.
  2. One visibility list per leaf, also optimised for speed (only the leaves that can actually be seen from another leaf should be there). It will probably require rather tedious calculations.
  3. A light map, that is used to make the rendering of surfaces more realistic. I have no idea how this can be handled.

2.1 General description of levels

A Quake level is basically organised around a huge BSP tree. All is derived from the BSP tree, and all depends on the BSP tree. So if you don't like BSP trees, forget about making Quake editors.

Of course, if you intend to edit Quake levels, chances are that you will never have to deal with the BSP tree itself. What you will edit is a rather complex 3D map, a bit like those of DESCENT, except that almost any shape is allowed, not only combination of cubes.

Quake will require a very clever 3D editor, because there seems to be quite a lot of things to calculate that can't entirely left to the user, light ambient lights, alignement of light maps and texture offsets.

2.1.1 Level boundaries:

The levels are considered by Quake only as a kind of entity, like any other entities, and it seems possible to put one level inside another. Although this sounds a bit strange, it could be useful in order to 'smoothly' transit from one level to the other. In DOOM or even in HEXEN, there is only one level displayed at the time, so transits between levels must be done via teleports. This may not be the case in Quake.

2.2 Level organisation

So here is the level organisation on a file. As mentionned before, it is a huge BSP tree. All the components of this tree are detailed below, but first here is a general description:

the BSP tree is made of nodes, starting with a root node, which has two childs, which in turn have two childs, and so on, as you go down the branches of the BSP tree. The nodes only represent a way to partition the space, they do no ever appear in a level.

Some of the childs are extremities of the branches. They are called BSP tree leaves, and in fact each branch must be terminated by one leaf. Those leaves are in fact portions of the actual 3D level, and usually they represent portion of rooms. So to any leaf is associated one or more surfaces, that represent the actual walls, floors, ceilings and sky for this portion of level.

Those surfaces are defined by a plane in which they lie, an ordered set of vertex, that define their boundary, an constant base light level, a single texture, and a light map and offsets for the texture.

The textures are defined by a reference to a picture or a set of animated pictures, some base offsets, and some flag that say if they must be flipped horizontally, vertically or both.

I seriously doubt you could make any sense of the above, so there is some more details, to add to the confusion. If by the end of this chapter you still don't understand how the level are organised, go play DESCENT to increase your experience with 3D volumes :-)

2.3 The Tree Leaves (Sectors)

The tree leaves are the Quake equivalent of the sectors in DOOM. You can imagine them as rooms, or part of rooms, where the monsters, players and object will be placed.

Actually the tree leaves are the equivalent of the Sub Sectors: each sector in DOOM is decomposed by the BSP into smaller and simpler convex sub sectors, that contain only part of the sector lines.

Technically, each tree leaf, made of some surfaces and bound by the BSP node split lines, appears in 3D space as a convex polytope.

Think of them as big rooms without any corners where you can hide from any part of the room. (Sorry, I'm just trying to be AOLicaly correct).

Well, if you don't understand the above, I'm real sorry but the best you can do is go ask your mother for a system upgrade.

Technically, a tree leaf is defined by

2.4 The Surfaces (Walls, floors and skies)

The surfaces represent the visible boundaries of a tree leaf. The surfaces are the Quake equivalent of the Sidedefs of DOOM, in the sense that they tell what sector boundaries look like.

Depending on the name of their texture, they will appear are a sky texture, or as a wall or floor (that can eventually be animated). Note also that though the skies are ordinary wall textures, they are drawn in a very special way, that make them look like skies. That is basically the same trick as in DOOM, except that it doesn't need to use a F_SKY fake sky marker.

The surfaces will be rendered as a texture-mapped polygon. The texture somewhat takes into account the distance, for better realism. Technically, the polygon is split based on the inverse of the distance, and fragments are mapped linearly.

The texture mapping also takes into account the orientation of the surface, because calculations of points in texture space is done by selecting only 2 coordinates among the three coordinates of the points. So depending on the orientation of the surface, the most representative set of coordinates must be chosen.

Technically the surfaces are defined by:

2.4.1 Open Passage ways

When a surface is just a passage way (like a hall, a door, or a hole in the floor) and need not be covered by a texture, it is just... ignored. There is nothing that describes it in the level structure.

This is a contrast with DOOM, where that kind of passage had to be indicated by two sided lines. There is no 2 sided surface, unless you want to create a transparent wall (and even then, it would be made of two independant surfaces).

2.5 Texture definitions

The texture definitions are not actual textures, but rather special references to the true textures. One or more texture definition can point to the same texture data, and it will look somewhat different each time.
There is no equivalent of this intermediary texture definition in DOOM.

Each texture definition contains:

2.6 Planes definitions

The planes are used as split planes in the BSP tree nodes, and as reference plane in the Surfaces.

They are the Quake equivalent of the DOOM Linedefs and Segments.

The planes are defined by a normal vector and a distance. This normal verctor must be of norm 1.

The plane equations are used for distance calculation and to determine if a given vertex (of a surface, or an entity) is on the front side or the back side of the plane.

It is highly recommended that if a node and some set of surface use the same plane equation, they point to the same plane definition.

2.7 Vertex definitions

The Vertex as the Quake equivalent of the DOOM vertex. the only difference is that they are in 3D, not in 2D.

There can only be 12 vertex per face, and in fact, 16 vertex when taking into account the clipping of the face by the BSP planes. In fact, there are so many limitations related to this 16 number of vertexes that we can expect it's only temporary.

2.8 BSP tree Nodes definitions

The nodes are the Quake equivalent of the DOOM nodes and also of the DOOM blockmaps. They are parts of a 3D BSP tree, not a 2D BSP tree like in DOOM.

The nodes are used for level display, placements of entities and collision detections (and maybe even more). So there is no need for a blockmap in Quake.

Technically, nodes are defined by:

The root node of the BSP tree is the first node in the list of nodes (in DOOM, it was the last node).

The front child node (and all the nodes below it) is entirely contained in the half-space that is in front of the split plane.

The back child node (and all the nodes below it) is entirely contained in the half-space that is in the back of the split plane.
(The 'front' and 'back' of a split planes are defined by the plane equation giving a positive or negative result for any given vertex)

If the split planes reference is -1, then in fact the node is a tree leaf, see the definition above.

2.9 Visibility list

This tricky structure is the Quake equivalent of the REJECT map of DOOM. And yes, it will take ages to calculate (I hope not!).

Unfortunately, it is much more important than the REJECT map, since it can be used to make the level rendering much faster. This is due to the fact that sectors are now the leaves of the BSP tree.

The REJECT map in DOOM was only used to control the monster's behaviour. It could not be used for rendering, since it was sector based.

So it can be expected that the REJECT special effects of DOOM (blind monsters and such) are something of the past... though in fact, screwing the visibility list is a very good way to obscure some areas of the levels. But I'm not sure Quake will be of much fun in blindfold mode.

Basically, the Reject map is an array of bits, one array per tree leaf. The bit number n, if set to 1, tells that when laying in the tree leaf, one can see the leaf number n.

When the player is in a leaf, the engine finds all the leaves that are visible from that leaf, and tag those leaves. Then it tags back all the nodes that are above the tagged leaves. That way, only the part of the BSP tree that is really visible will actually be tagged, and later displayed.

2.10 Lighting

Recent information released by id software indicate that the light mapping and shadowing in Quake would be done dynamically. The fact that everyone thinks it's damn impossible to make any dynamic shadowing on a 486 or pentium is only a minor concern.
I sincerly hope that the description below is outdated.

Quake apparently uses some static light model: the shadows are not calculated for each moving sources, but are pre-determined once for all when the level is finished, taking into account the light sources existing at that moment.

There is no Gouraud or Phong shading calculated in real time. It happens that those hyped shading models are rather meant for curved objects approximated by polygons. Since Quake levels are polygons, not approximations, there is absolutely no reason to use Gouraud or Phong.

The way Quake makes it's surface lighting so realistic is a bit special. It works with each surfaces independently of others, and the lighting is only calculated once for a set of similar surfaces.

The basic idea behind the Quake lighting is to take into account 3 things:

Constant light level

The basic lighting principle is that of so-called 'flat shading'. All the points in a given surface have the same basic light level.

There is one such light level for each surface, and we can assume it depends on the orientation of the surface, and on the static light sources defined before the level is calculated. I suppose that a good Quake editor would let the user define some sources of lights (windows, torches, sky) and then do the lighting calculations once and for all, for all surfaces. Of course, this is fairly primitive (no way to move torches, to switch off lights) but then again the game engine could possibly update this static light in real time, under certain conditions.

It could be that this basic light level, like in DOOM, can evolve dynamically, depending on action on switches. It is even possible that it is calculated in real time, taking into account the moving light sources. That would make only a very crude approximation of a shadow, but maybe that is enough.

Type of lighting

This strange attributes seems to translate internally into some kind of multiplicator for the light map below. Apparently, it only multiplies the light level, it doesn't affect the colors. I supppose it's here to give a bit more variability to light maps.

Light Map

The light map, basically, is a byte field, one byte per pixel of the texture. This byte give the light level of this pixel. This allows for some fairly realistic apparent surface irregularity. However, the light map is not defined for each pixels: it's only one light value every 16 pixels, and it is bilinearly interpolated in the intervals. Also, a light map can be shared by more than one surface.

Pixel Lighting

Using the pixel's color index, and the light level calculated as: light(x,y) = lightmap(x,y) * lightstyle[style] + constant light

This light level is used to select an internal color palette. Then using the texture's color index and an index in this palette, it's possible to find the actual lighted color. This mechanism is basically the same as in DOOM, except that there is 256 (?) color palettes, not 32. This mechanism takes into account both 8-bit or 16-bit color palettes, so Quake will look better on 16-bit per color display, but will still run on 8-bit per color display.

Dynamic light mapping

Franckly I have no idea how this could work. However, the static light mapping is already so calculation intensive that I wonder if, after all, a simplified dynamic light calculation wouldn't be as fast. Descent is supposed to do light calculation for every vertex of the cubes, and then apply linear mapping between the vertex. A similar technique could be used in Quake, but it would probably involve much more vertex calculations.

2.11 Model format

This is the format of the model, when stored in a single lump.
        
                DELETED BECAUSE OBSOLETE

         The format will probably be some ASCII.

2.12 The Quake 3d engine: rendering of levels

(Thanx to Jens for some critical reflexions)

I'm not going to explain in details how the Quake 3d engine works. It wouldn't be fair to id software, and anyway I still don't understand a lot of critical features. Also, if such an explanation was to be read by the conceptors of Quake, chances are that they would die laughting, and I don't want to take that risk.

Let's say only that the Quake 3D engine looks like an ordinary texture-mapped polygon engine, where the polygon sorting is not done via classical backface elimination and distance sorting, but by using a BSP tree. Of course, there are many more clever tricks, which are not supposed to be made public.

Countrary to DOOM, there is no ray-casting, so some surfaces are sometime rendered, then later overwritten by closer surfaces. Hence the visibility list is critical for this engine, otherwise it might really crawl.

The Quake engine bears definitely no relation to the Descent level display engine, though there might be some similarities with the engine that display the vessels of Descent.

Well, this description gives only the general features of the Quake engine, and actually don't make a lot of sense. Here are some temporary conclusions:

This part will be updated later.

3. The 3D Alias Model Format

Alias models can be used for entities, like players, objects, or monsters. Some entities can use sprite models (that are similar in appearance to those of DOOM, though the strucutre is totally different) or even maybe models similar to those of the levels.

3.1 Organisation of Alias Models

Technically, an alias model is defined by:

How does it work?
First imagine a wireframe model of the entity, made of triangles. This gives the general shape of the entity. For instance, imagine you have the general shape of a cow, made of triangles in 3D space.

The extremities of the triangles are the 3D vertexes, and countrary to level models, there is no need for elaborate stuff like nodes, planes, polygon surfaces. Only triangles and vertex.

Now, there is something missing: the skin. A cow without skin looks pretty ugly.
Imagine that you have a flat carpet made of the skin of an unlucky cow. All you need to do is put some parts of this carpet at the relevant place on the wireframe model of the cow, and you'll get a fairly realistic (though a bit polygonal) cow.
That's the way if works with the alias models.

For each triangle in the wireframe model of the cow, there will be a corresponding triangle cut from the skin picture. Or, in other words, for each 3D vertex, extremity of a triangle, there will be a corresponding 2D vertex positionned on the skin picture.

It is not necessary that the triangle is 3D space and the triangle on the skin picture have exactly the same shape (in fact, it is not possible for all triangles) but they should have shapes roughly similar, to limit distortion and aliasing.

That's all Quake needs to display an alias model. It's quite easy to understand, but unfortunately editing such a structure may be troublesome.

3.2 Animating alias models

Once the general shape of the model (for instance, a cow) is defined, and the skin is mapped correctly on that shape, animation is pretty straightforward: just move the triangles around and it will seem to move.

To move the triangle, you need only modify the position of the 3D vertexes at the extremity. For instance, to move the leg of the cow, you will move the vertexes that define the extremity of the legs. You will also move the other vertexes a bit, so that the movement looks less mechanical.

Chances are that creating a fine looking animation is gonna be a very tough job, a bit like with the DOOM sprites. I would bet that the quality of the animation will be the most critical point.

Note that the animation consists only in changing vertex positions (and that's why there is one set of vertexes for each animation frame).
The skin of the cow is not modified, neither are the definition of the triangles. So blood stains cannot suddenly appear on the skin, and parts of the cow cannot fly away, separated from the rest.
That is... unless you use some tricks, that I leave to your imagination.

Note also that the animation is based on frames, like in DOOM. The animation is defined once and for all, and there is no squeletal model or any similar physical model involved in the calculations of the movements.
Of course, nothing in the structure of the Alias model strictly forbids to use a physical model for the entity.
But is much more clever to write some well thought program to control the animation sequences (and Quake allows that) than to waste precious time calculating some approximate physical model.

3.3 Rendering of alias models

The rendering of entities is a bit more complicated than the ordinary back-face elimination and triangle sorting that is common in games like X-Wings, Terminal Velocity or the like. It doesn't use a BSP tree like Descent (or so they say), but it takes into account the BSP tree structure of the Quake levels.

There is no need to bother about the engine. Just keep this in mind:

3.4 Alias Model format

                DELETED BECAUSE OBSOLETE

        The format may become some ASCII.

        All you need to know is that there is only one picture, and
        that frames are done with vertex, rather than with changes in
        the picture.

4. Sound capabilities

You will find here some indication concerning the sound support, but nothing really reliable.

Sound format

Quake is using WAVE file as input, but, surprisingly, instead of the expected 16-bit stereo, these are 8-bit mono sounds!

The sound has to be mono, not stereo, because the stereo effect is calculated by the game, for spatialisation.
It is possible that the 16-bit sound drivers are not yet written, but actually since Quake uses many channels and different volumes per channel, the sum is tantamount to a 16 bit sound.
Note that the 3D engine is using a similar trick: 256 color textures, converted to 16 or 24 bit colors by using lights.

Now, the file format: the expected file format is WAV, but in fact the sound loading code is really simplified, and only a very special sub case of the WAV format is tolerated: a 8 bit mono sound, with no special features and especially no built-in comments.
If you are using a good WAV program, it is possible that it uses a more complex format. So don't be surprised if your file is rejected.

Location of sound sources toward player

The sound spatialisation is done by using a simplified model, that doesn't take into account difference in phases, and echoes.

Basically, the sound itself is not modified, only the volume of the right and left channels are affected.

This looks pretty basic, but it works. I wonder if it won't make people a bit dizzy, though, if they use VR set. That's because the ear will have to addapt to this strange kind of spatialisation.
Of course, the sound spatialisation may later be made more realistic.

Supported sound cards

The only certitude is that the Sound Blaster will be supported. But which flavour of SB, I haven't the faintest idea.
There is no part dedicated to the GUS, but there is a part dedicated to the handling of channels via the DMA. It can be expected that most popular sound cards will be supported via this method.
Anyway, this is not very important. The only troubles will be for PCMCIA sound cards, since they cannot use the DMA (or so they say).

Music

There is no music. No hint whatsoever of something that could feed a MIDI device. Not even a mention of MUS stuff. Get a CD player!

5. The network capabilities

This area is being investigated.
Results of investigations will be published here only if approved by id software. As a matter of fact, the network capabilities and the protocol used are considered as a trade secret. Only what is strictly necessary to game play will be detailed here.

Let's just say that Quake maintains a representation of the world were entities can be added an removed dynamicaly, and players can log in at any moment. Not really surprising...

The server seems to sends continuous updates the clients, but these updates are non-synchronous, contrary to DOOM. That means server and clients go at their own pace, but it's the server that keeps track of the game time.

The data exchanged is not compressed, and thus only suitable for transmission over a LAN, certainly not a 14.4k modem. This will change.

This part will be updated later.


6. Miscellaneous Information

Here you will find some obsolete descrition of various stuff that don't make a lot of sense yet.

6.1 The Quake Programming Language

This language is very similar to C. It is loaded dynamically by the server, read, and transformed in an internal representation.

The description of the language here is totally outdated. It was probably rewritten for efficiency. Since it must be parsed during the game play, it had better be simple to parse, so the C-like syntax will have to be improved.

The names of variables in the code are reminiscent of MUDs code, and there is all reason to believe Qu*ke will be MUD-like.
Of course, there isn't much code compared to even the simplest MUDs.
There is code that describe how the Qu*ke server should handle the clients, as they join an existing world. BTW, they can join dynamically, like in DESCENT. And they can join the level they wish.

The Things are all represented by C-like objects, with a set of attributes whose name are fairly intuitive (frags, velocity, health...) and the language provides a set of functions of the basic stuff.

Vectors values are represented as character strings like "1 2 3", and can be added, scaled and multiplicated. The attribute think is used to tell or what code function the object shall apply. The attribute nextthink is used to tell when the next call to the object's code shall happen.

Like in DOOM, the Object/monsters will be implemented as finite state automats, based on frames. But you won't need DeHacked to read them. The Objects frame tables are provided in the code (with a special macro structure, that expands trivialy into code)

Programmer's Corner

The language seems syntacticaly clean, but there seem to be no strict type checking anywhere, so odds are that any complex code module will be real difficult to debug. Not to mention the 'goto' lying around. I wonder what happen when one mixup frames from different monsters... Apparently the language is entirely event driven (not a surprise) and timers can be set for certain events. Mind the event loops!

No details will be given on the actual code: the parser and probably the language were rewritten by id, for more efficiency.

It is not known if some fair level of AI can be implemented using this language. I seriously doubt it is possible to manipulate some accurate representation of the world. Quake isn't really a wargame, is it? ;-)

6.2 List of Entities

The entities represent the monsters, players, objects and probably various other stuff.
Each type of entity is much like an object class, with a list of parameters that define various default parameters, like the model used fo represetn the entity, the Quake Programming language file that defines the behaviour of the entity (the 'think' parameter) and similar properties.

Here is an example of entity type definition. It looks like some LISP syntax, with { } instead of ( ). This is probably because the parsing of LISP syntax is real easy and non-ambiguous.

{
  {classname   "bestiole"}
  {color       "1.0 0.9 0.4"}
  {orgofs      "64 64 80"}
  {size        "32 32 70"}
  {model       "s_bestiole"}
}

6.3 Light maps

This information is probably totally outdated.

The light maps were a trick used in early versions of the Quake engine. It was a way to implement some cool shadows without too many calculations involved. Countrary to what was supposed initially, it bears no relation to dynamic changes in the light level.

Example:

ccmdefabcdefgmmmmaahijlkmmaamm 9 BOUGIE (third variety)
See the level description to know how these light maps are used in levels. They don't seem to be used with entities.

6.4 Player Movements

There are some reasons to believe that there is no restriction in 3D movements Quake. 6-axis movement seems technically possible, and at least the movement internal structure allows all combinations, and the graphic engine is not restricted to any rotation.

Here are the known movements:

 turn left/right, up/down, 
 move front/back
 strafe left/right, up/down
no key is defined for roll turn, jump, climb, fly. This may/should change.

6.5 The Language of the Gods

The language of the Gods, countrary to common Tleilaxu beliefs, is C. It was C in DOOM, it is C in Quake.

Let's just say that the code if id is characterised by... the absence of almost all security tests. That means that if the data structures are not 100% perfect, the code will bug or crash without warning. This is especially true when you deal with indexes. Don't even make a mistake on an index, in a file.

It can be noted that the code was not optimised at all and used floating numbers (and thus, used the floating point unit). This makes it especially unsuitable for 386 (no surprise) and in fact unsuitable for anything below an helium-cooled 300 Mhz 686, with 500k of primary cache and 20 meg of s econdary cache. However the code was certainly completely rewritten and optimised since these first experiments, and it will run at decent speed even on a DX2/66 (Or, shall I say, DESCENT's speed. At least.)


7. Final Word

This material is provided to you as general information.
You are in no way obliged to believe anything of the above.

Last remark: this document was written quickly, and I'm not that proficient in English. So it's full of mistakes.

Nezu the Unworthy

Come visit my Home Page for the last updates to this specification.
List of cool Quake Related pages:


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